Ore grader



March 20, 1962 T. E. YETTERLAND 3,025,961

ORE-GRADER Filed Oct. 11, 1957 2 Sheets-Sheet 2 1} INVENTOR.

.U ivy/456 )mwmw United States Patent ()filice 3,025,961 Patented Mar. 20, 1962 3,025,961 ORE GRADER Thomas E. Yetterland, Minot, N. Dak. Filed Oct. 11, 1957, Ser. No. 689,665 2 Claims. (Cl. 209-73) This invention relates to apparatus for grading ore and more particularly relates to such apparatus for separating high grade radioactive ore from lower grade ore.

Uranium oxide, a radio active material, is not ordinarily found in bedded deposits in the natural state. On the contrary, the deposits are found in a host rock or conglomerate and are very irregular and erratic. The percentage of uranium oxide will not only vary throughout the lode, but will vary in disposition on the adjacent grains of silica.

An object of my invention is to provide a new and improved ore grader and separator of relatively simple and inexpensive construction and operation.

Another object of my invention is the provision of a 'novel ore grader and separator which is constructed to utilize the irregular and erratic disposition of a mineral in a host rock or conglomerate as an important factor in grading and separating the valuable high grade ore from the substantially useless host rock or tailings.

A further object of my invention is to provide a novel and improved radio active ore grading mechanism which divides the ore into different segments and progressively moves said segments in pulses or jumps so as to efiectively divide the segments into a multiplicity of relatively small quantities of ore which may be readily analyzed and collected as high grade ore or tailings.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIG. 1 is a front elevation view, partly broken away, of the invention;

FIG. 2 is a top plan view of the ore grader;

FIG. 3 is a transverse section taken on a substantially vertical plane as indicated at 33 in FIG. 1;

FIG. 4 is a detail elevation view in an enlarged scale showing the discharge end of the conveyor;

FIG. 5 is an enlarged detail section view taken on a substantially vertical plane as indicated at 5-5 in FIG. 2;

FIG. 6 is a detail elevation view, partly broken away, and showing a modified form of the invention; and

FIG. 7 is an enlarged elevation view, partly broken away and showing another modified form of the invention.

The radioactive ore grading and separating mechanism, which comprises the present invention, is provided with a suitable supporting structure which is indicated in general by numeral 10. The mechanism includes material-supplying apparatus 11, material-segregating and grading mechanism 12, ore concentration detecting mechanism 13 and the material discharging mechanism 14.

The material-supplying apparatus 11 includes a receiving hopper 15 into which ore and the host rock or conglomerate is supplied by suitable transporting mechanism such as a front end loader on a tractor or the like. It is desirable that the hopper 15 be substantially identical in width to the width of the loading shovel or bucket so as to minimize the disturbance or agitation of the conglomerate and ore, at least in a direction across the width of the conveyor and hopper 15. To this end, the end walls of the hopper 15 are substantially vertical.

The discharge opening at the bottom of the hopper 15 extends across the entire width thereof and supplies the ore-conglomerate mixture into a crusher mechanism indicated in general by numeral 16 and having togglemounted face plates 17 movable toward and away from each other for discharging material therefrom at a relatively uniform size. It should be understood that the crusher face plates 17 extend across the entire width of the hopper 15, so as to produce as little disturbance in the relative dispositions of the ore and conglomerate relative to each other. It is to be understood that the showing of this particular type of crushing mechanism should not be limiting to the form of the invention, because other types of crushers may be employed. The crusher 16 discharges the ore-conglomerate mixture onto the material-segregating and grading mechanism 12.

The mechanism 12 includes a reciprocating and oscillating type conveyor which is indicated in general by numeral 18 and which is supported at its receiving or rear end portion by suspending links 19 which are swingably connected with the supporting structure 10 and with suitable mounting ears 20 on the conveyor, and also by an eccentric cam 21 which underlies the forward portion of the conveyor 18 and is affixed to a drive shaft 22. The drive shaft 22 is suitably journalled in bearings at the opposite sides of the conveyor 18 and on the supporting structure 10. Drive shaft 22 is drivably connected with a source of rotary power, such as motor 23. The conveyor 18 is oscillated by a pitman oscillator having a rotary drive member 24 fixed on the drive shaft 22 and rotatably connected by driving pin 25 to a reciprocating drive link 26 which is also connected by pin 27 to an ear 28 which is aifixed to the conveyor 18. It will be noted from the arrangement shown that the conveyor 18 moves with a generally for- 'wardly and rearwardly motion and the rear end portion will swing upwardly as the conveyor approaches the forward limit of its stroke. In addition, a substantially vertical, upward and downward motion is imparted to the forward end portion of the conveyor 18 by the eccentric cam 21.

Because the material-supporting deck 29 of the conveyor 18 is inclined, the material supplied from the crusher 16 onto the rear portion of the conveyor, moves in pulses or with a periodic jumping motion toward the lower forward end portion.

Means are provided on the conveyor 18 for defining a plurality of juxtaposed material-segregating fiow channels from the receiving end to the discharge end and in the form shown, such means includes a plurality of upright, longitudinally extending divider walls 30 which are arranged in parallel and spaced relation to each other and to the outer material-confining walls 31 at the sides of the conveyor deck. The walls 31 are aifixed to the deck 29 and extend throughout the entire length of the reciprocating conveyor so that the material supplied to the conveyor is immediately segregated upon receipt thereof and is segregated until grading has been accomplished.

The conveyor deck 29 has a plurality of high concentrate ore-discharging openings 32 therein adjacent the lower or discharge end, and each of the openings 32 extends between adjacent material-retaining walls so as to accommodate therethrough the entire flow of material through the particular channel 33 when opened. Means are provided for directing the flow of material moving forwardly through the several channels, into the openings 32 or over the forward discharge edge portion of the conveyor and in the form shown, such means include a plurality of material-directing or movable gate mechanisms which are indicated in general by numeral 34 and which include a shiftable gate 35 which is movable into and out of flow-obstructing relation in opening 32, and

in the form shown is movable in reciprocation. A solenoid 36 is provided for each of the gate mechanisms and is affixed to the lower surface of the conveyor deck. The armature 37 of each of the solenoids 36 is connected with a depending web 43 which is afiixed to the gate 35 for moving the same. The gate 35 may he slidably supported at its opposite edges as by channels 38 'affixed to the deck 29.

Each of the gate mechanisms is provided with means for obstructing flow of material through the corresponding channel at a location forwardly from the opening 32 when the same is open, and in the form shown, such means include a vertical gate 39 in alignment with a 'slot 40 in the deck 29, and guided for vertical movement in grooves 41 which are formed in the channeldefining walls 30 and 31. Gate 39 has a roller at each end thereof which engage the cam surfaces 42 of the vertically disposed webs 43 which are affixed to the gate 35 at the oppsite sides thereof for reciprocatingr'riovement. As the webs 43 move rearwardly, the rollers 44 move along the camming surfaces 42 and move the gate 39 upwardly through the slot 40 and in the channels 41 for obstructing the fiow of material through the channel and at the same time direct all of the material flow downwardly through the high concentrate opening 32.

The on concentration detecting mechanisms 13 include a plurality of radioactivity detectors indicated in general by number 45, each of which is mounted on the conveyor 18 immediately above a corresponding channel and slightly behind the corresponding opening 32 in the deck. Each of the detectors is constructed so as to be highly directional in nature whereby to be responsive to only the material immediately therebelow in the Channel. To this end, an open-bottomed, but otherwise enclosing shielding 46 is provided for each of the detectors. Each of the detectors also includes a radioactivity responsive tube 47 which may comprise a Geiger-Mueller tube or a detecting crystal and photomultiplier tube. The tube 47 is responsive to the gamma ray bombardment of the radioactive material in the channel therebelow. Each of the detectors 45 includes cooperating control mechanism in a control box 48 which includes such items as an amplifier, a voltage source, a radioactivity meter and controls for the tube 47. Of course the tube 47 is electrically connected with the control mechanism in box 48, and furthermore an operative connection (not shown) is provided between the control mechanism in the box 48 and the solenoid 36 of the gate mechanism. The solenoid 36 will be operated in response to a predetermined concentration of radioactive ore immediately beneath the detector tube 47 so as to open the gate 35. The control mechanism in the box 48 may be adjusted as by knobs 49 so as to vary the level of concentration of radioactive ore beneath the detector tube 47 necessary to operate the solenoid 36. Whereas each of the detectors measures the concentration of ore in each of the respective channels, an integrating device may be provided for obtaining a response in relation to the overall quantity of radioactive ore at all points across the conveyor.

The material discharging mechanism 14 includes a pair of material-carrying belt conveyors 50 and 51 which are disposed beneath the forward edge of conveyor deck 29 and below the high ore concentrate discharge openings 32, respectively, for receiving and carrying the tailings and the high concentrate ore respectively.

In operation, the ore-conglomerate mixture is supplied into the hopper 15, through the crusher 16 and onto the conveyor in the manner hereinbefore set forth so as to minimize mixing of the materials, at least in a direction transversely of the conveyor. The material is immediately segregated as it falls onto the conveyor, and a portion falls into each of the channels 33. Because of the upwardly swinging, oscillatory motion of the rear portion of the conveyor and because of the generally reciprocating movement of the entire conveyor along with the substantially vertical reciprocation of the forward portion of the conveyor, the material moves forwardly through the channels in pulses or periodic jumps. It should be recognized that during a certain portion of the cycle of operation of the conveyor, the material is relatively stationary on the deck. As a result, the material, as it moves into position beneath the detector tube 47 is substantially stationary for a period sufliciently long as to permit the tube 47 to react if the material immediately therebelow has a sufiicient concentration of radioactive ore. In the moment that the segment of material below the tube 47 pulses forwardly, the solenoid will have been operated by the control mechanism in response to the indication produced by the tube 47 and the high concentrate se ment of ore will fall through the gate opening 32 an onto the conveyor 51. Simultaneously, asthe gate 35 opens, the channel-obstructing gate 39 shifts upwardly to make sure that all this high concentrate ore is discharged downwardly through the opening 32. As this segment of ore is falling downwardly through the opening 32, the detector tube 47 is already scanning the next adjacent segment of mixture to determine the concentration of radioactive ore therein. If the ore concentration in this next adjacent segment is sufficiently high the gate 34 remains open and the segment of ore falls through the opening 32. In this manner, the high concentrate ore moves in pulses through the opening 32. It should, however, be noted that if a segment of ore which is scanned by the tube 47 does not have a sufficiently high concentration of radioactive die as to produce the necessary indication for operating solenoid 36, the gate 35 will remain closed and the gate 39 will remain in its downwardly shifted position out of obstructing relation with the material in the channel.

It should be specifically noted here that each of the detectors 45 and a corresponding gate mechanism 34 operate together, but independently of any of the other detectors and gate mechanisms so that a highly accurate and precise grading and separation of the ore from the conglomerate will result. The mass of ore and conglomerate supplied to the conveyor is divided into a plurality of narrow segments and is then effectively divided into a plurality of short lengths which are individually scanned for the concentration of radioactive ore.

The modifications shown in FIG. 6 and FIG. 7 are substantially similar to the form of the invention shown in FIGS. 1-5. The form shown in FIG. 6 includes a conveyor 60 having a material-carrying deck 61 with a plurality of channel-defining upright divider Walls 62 thereon and a high concentration ore discharging opening 63 therein. A flop gate 64 is swingably mounted on a pivot pin 65 and has a control arm 66 connected to the armature linkage 67 of the gate operating solenoid (not shown). The forward end portion 64a of the gate 64 is arranged to swing upwardly into the channel into the dotted position B shown for obstructing flow of material through the channel as the opening 63 is opened for discharging high concentrate ore.

The form of the invention shown in FIG. 7 includes a conveyor 70 having a deck 71 upon which are mounted a plurality of upright channel-defining divider walls 72, and in which is formed a high concentrate ore discharging opening 73 in each of the channels. A swinging gate 75 is hinged at its forward end by a control shaft 76 to which is connected a swing arm 77 for turning the gate in response to reciprocating movement of the solenoid armature linkage 78. Another arm 79 is disposed at one side of the channel and is afiixed to the shaft 76. The arm 79 is swingable upwardly through an elongated slot 86 at one side of the channel, and is connected by means of an elongated flexible element such as cable 81 which is trained over pulley 82 to a vertically movable channel-obstructing sliding gate 83 which is mounted in channels 84. These modified forms of the invention produce results substantially similar to that shown in FIGS. 1-5 and in both cases the control gate for the high concentrate discharge opening is operated by the solenoid.

These gate constructions are advantageous for use in graders utilizing certain types of ore because of the different manners in which the gates are opened.

The form shown in FIG. 6 obstructs the flow of the ore concentrate mixture to the tailings discharge edge by the upwardly swingable forward end portion of the flop gate. The form of the invention shown in FIG. 7 permits the vertically slidable gate 83 to move downwardly as the high concentrate discharge opening 73 is opened.

It will be seen that I have provided a new and improved radioactive ore separating and grading mechanism which segregates the ore into elongated segments and subsequently effectively segregates each of these elongated segments into small quantities by moving the ore in pulses along the conveyor whereby each of these small quantities of ore-conglomerate mixture may be scanned for radioactivity concentration with a high degree of accuracy and to thereby be highly selective as to the ore which is to be salvaged and the conglomerate or tailings which is to be discarded.

It will, of course, be understood that various changes may be made in the form, detail, arrangement and proportion of the parts without departing from the scope of my invention which consists of the matter described herein and set forth in the appended claims.

What is claimed is:

1. Apparatus for grading crushed radioactive ore comprising an elongate conveyor having an ore supporting deck for carrying ore thereon in a thin stratum longitudinally from the material receiving end to the discharge end thereof, divider means mounted on said deck defining a plurality of parallel juxtaposed channels extending longitudinally of said conveyor for dividing the ore thereon into a plurality of narrow laterally separated elongate streams of material, means for actuating said conveyor whereby the ore is intermittently vibrated and progressively moved longitudinally thereof in step by step fashion and whereby said narrow streams of ore are subdivided into a longitudinal series of small substantially separated segments, and separate classifying means for each of said channels, each of said classifying means comprising a discharge opening in said deck adjacent the discharge end of its respective channel, a gate for opening and closing said discharge opening, and a detector sensitive to and capable of being actuated by the radioactivity of the ore being classified positioned adjacent said discharge opening and adapted to successively scan and be actuated by only the individual segments in its respective channel as they are delivered thereto, said detector being responsive to and actuated by segments having a high concentration of radioactive material and unresponsive to segments having a low concentration of radioactive material, and means operatively connecting said detector with said gate for opening and closing said gate in accordance with the reaction of the detector to each of the segments scanned thereby whereby said segments after being scanned by said detector are dropped through said opening or passed thereover according to the degree of concentration of radioactive material in each of said seg-.

ments to thereby separate the segments having a high concentration of radioactive material from those segments having a low concentration of radioactive material.

2. Apparatus for classifying crushed radioactive ore comprising a supporting structure, an elongate conveyor having an inclined material supporting deck sloping downwardly from the material receiving end thereof to the material discharge end thereof for carrying the ore to be classified in a thin stratum thereon, a plurality of elongate parallel laterally spaced apart divider walls mounted on said deck longitudinally thereof defining a plurality of juxtaposed channels for dividing the thin stratum of material into narrow laterally separated elongate streams of material, means for repeatedly reciprocating and vibrating said conveyor whereby the material carried thereon is intermittently moved in step by step progression towards the discharge end and whereby each of said narrow streams are subdivided by said movement of the conveyor into a longitudinal series of small substantially separated segments, and separate classifying means for each of said channels, each of said classifying means comprising a discharge opening in the portion of the deck underlying its respective channel and adjacent the discharge end thereof, a movable gate for opening and closing said discharge opening, and a detector sensitive to and capable of being actuated by the radioactivity of the ore being classified positioned adjacent said discharge opening and adapted to successively scan and be actuated by only the individual segments in its respective channel as they are delivered thereto, said detector being responsive to and actuated by segments having a high concentration of radioactive material and unresponsive to segments having a low concentration of radioactive material, and means operatively connecting said detector and said gate for opening and closing same in response to the reaction of the detector to each of the segments scanned thereby whereby said gate is opened when the segments scanned by the detector have a high concentration of radioactive material and said high concentration segments fall through said discharge opening and whereby said gate is closed when the segments scanned by the detector have a low concentration of radioactive material whereby said 10W concentrate segments pass over said discharge opening and continue their movement along their respective channel.

References Cited in the file of this patent UNITED STATES PATENTS 788,618 Widney May 2, 1905 1,197,697 Weller Sept. 12, 1916 1,678,884 Sweet July 31, 1928 2,016,204 King et a1. Oct. 1, 1935 2,501,403 McKinsey Mar. 21, 1950 2,617,526 LaPointe Nov. 11, 1952 2,707,555 Gaudin May 3, 1955 2,717,693 Holmes Sept. 13, 1955 FOREIGN PATENTS 261,230 Italy Nov. 16, 1928 478,287 Canada Nov. "6, 19 51 

